can any body tell me about this plant?

It's papaver somniferum, aka the opium poppy. An annual, you can harvest the seeds for culinary use or to broadcant them around the garden for some more next year. In this climate, they don't ripen enough for the narcotic gum.

Papaver somniferum. also known as opium poppies. Opium is the sap extracted from the seed pod. In this country we don't get enough sunshine for it to manufacture the opiates,from which is made, codeine, dihydrocodeine, diamorphine(heroin) and morphine.

No, but it will have lots of seeds. If you scatter them around or save for next year and then scatter in spring, you will have lots of plants next year. You must thin them to about a foot apart to get big plants and lots of big flowers.